All superstition is based upon ignorance more or less gross. Minds not capable of close and just discrimination are peculiarly liable to it. A carnal state of the heart works up the imagination, and the fleshly mind seizes with great vigour upon its own conceptions. When one has not been made wise by God’s word, and the affections become highly excited, plausible pretences are sufficient to mislead. Once enlisted in the cause of superstition, self-love causes persistence in it. Having some persuasion that holiness is essential, and the natural heart rising in opposition to the requirements of God’s law, the excited mind perversely seeks out some method whereby to delude itself into the persuasion that it is holy. The growth of superstition is by a very gradual process. Its whole history is written in three words, little by little. The only sure defence against it is the true knowledge and genuine love of God, accompanied by a firm determination to do what he commands, to worship as he directs, and to follow human devisings in nothing.
- William S. Plumer (The Law of God as Contained in the Ten Commandments, p. 230)